Current Concepts of Airway Management in the ICU and the Emergency Department

C. Byhahn, D. Meininger, and B. Zwissler

z Introduction

Effective airway management is a central part of emergency medicine, and many consider it as an undisputable core skill for emergency physicians [1]. The failure to establish and maintain adequate gas exchange can be catastrophic and may have important medicolegal implications. Emergency airway management in the field and in the emergency department is often challenging for the physician in charge. Trauma patients pose specific airway problems: unfavorable conditions (e.g., dark- ness, inadequate space, limited access to the airway, poor patient positioning, un- known assisting personnel with different levels of training, etc.) contribute to failed endotracheal intubation as much as patient peculiarities, e.g., oropharyngeal or pulmonary hemorrhage, facial trauma, or immobilized cervical spine. All these factors, as well as poor skills of physicians themselves, result in a difficult airway in 7±10% of patients who require emergency endotracheal intubation in the field or in the emergency department [2±4]. Airway management in the intensive care unit (ICU) can also be challenging, but mostly for reasons other than merely establishing an airway. Particular lung diseases or ventilation strategies require lung separation, either to prevent spread from the diseased to the healthy lung (e.g., blood, pus, etc.), or to independently ventilate both lungs with different ventilation strategies (e.g., after unilateral lung transplantation). Regardless of the fact that, during the last year, a number of clinical studies and a recent meta-analysis [5] have advocated performing early tracheostomy within the first 48 hrs of intubation, delayed tracheostomy on days 7±10 of intubation is still the prevailing practice of most intensivists. Apart from new aspects in tracheostomy timing, another innovative tracheostomy technique is recently being introduced ± balloon facilitated percutaneous tracheostomy. z The Unanticipated Difficult Airway during Emergency Endotracheal Intubation

Endotracheal intubation is classified as difficult when successful placement of an endotracheal tube by conventional laryngoscopy a) requires more than three attempts or b) takes longer than 10 minutes. While the prevalence of difficult intubation ranges from 3.0±8.5% in elective patients, emergency endotracheal intubation is more likely to be difficult (7±10%), regardless of whether intubation is attempted 378 C. Byhahn et al.

Table 1. Alternative devices for managing the difficult airway

Common supraglottic airways z Laryngeal mask airway z Intubating laryngeal mask airway z Laryngeal tube z Esophageal tracheal combitube Different laryngoscope blades z McCoy laryngoscope z Dærges universal laryngoscope blade z Straight blades (Miller, Foregger, Philipps, Henderson) z Videolaryngoscopy Fiberoptic devices z Bonfils intubation fiberscope z Bullard laryngoscope z Flexible fiberoptic bronchoscopy

in the prehospital or hospital environment. Several factors have been identified con- tributing to this higher prevalence. Amongst them are lack of practice, limited availability of alternative airways, difficult environmental conditions such as poor lighting, unfavorable patient positioning and poor accessibility of the airway (e.g., in entrapped patients). In addition, patient-related challenges, such as facial trauma, soft-tissue injuries of the neck, suspected cervical spine injuries, and oropharyngeal or pulmonary bleeding can lead to a difficult airway situation. Indications for emergency endotracheal intubation in Central Europe are mostly cardiorespira- tory disorders (80% of cases) [6]. The most frequent indication for airway interven- tion is cardiac arrest. Most endotracheal intubations in the emergency setting are performed successfully. In a small percentage of cases, an airway cannot be secured. When this hap- pens, emergency physicians may find themselves in a dangerous situation. The ability to quickly apply a rescue technique to establish an airway is essential to prevent hypoxemia and subsequent death. A variety of techniques has become available either to sufficiently insufflate oxygen, or to intubate the patient's trachea with devices other than a standard laryngoscope (Table 1).

Bag-Valve-Mask Ventilation Bag-valve-mask (BVM) ventilation provides immediate ventilation and oxygenation. In elective patients, the incidence of difficult BVM ventilation ± defined as an arte- rial oxygenation <90% during ventilation with 100% oxygen ± is 5%, whereas impossible mask ventilation is very rare (<0.1%) [7]. Under emergency conditions, however, BVM ventilation performed by both emergency physicians and health-care professionals may be insufficient due to lack of experience with this technique, re- sulting in an increased risk of gastric inflation with subsequent regurgitation and pulmonary aspiration. The incidence of significant pulmonary aspiration was 12.4% and 29.0%, respectively, under BVM ventilation in cardiac arrest victims [8, 9]. Beyond poor manual skills and too large tidal volumes, a sudden decrease of the lower esophageal sphincter tone after cardiac arrest (from a normal of 20 cmH2O to less than 5 cmH2O within 6 minutes after cardiac arrest) leads to gas- Current Concepts of Airway Management in the ICU and the Emergency Department 379 tric regurgitation [10]. BVM ventilation should therefore only be used as an initial manner to buy time until a more appropriate airway management technique is available and finally established. z Supraglottic Airways

Laryngeal Mask Airway A variety of supraglottic airway devices has become available in recent years (Ta- ble 1). The most popular and best evaluated item is the laryngeal mask airway (LMA), which was invented in 1985 [11] and is used in many anesthetic proce- dures. Beyond its routine use in the operating room, numerous studies have documented the usefulness and efficacy of the LMA in airway emergencies and under difficult conditions, such as cardiac arrest, in trauma patients, and even its efficacy and safety when used by non-physicians [12]. The LMA does not protect the trachea from aspiration of regurgitated gastric contents, but has been demonstrated to lower the incidence of gastric insufflation, regurgitation, and significant pulmonary aspiration when compared to BVM ventilation. Its insertion is easier to learn than endotracheal intubation, can be taught successfully on mannequins, and is superior to BVM in delivering adequate ventilation. Success rates of insertion are >95%, and there is evidence that the LMA may avoid some of the morbidity seen with emergency endotracheal intubation [13, 14]. The LMA is available in different sizes from infants to adults and, recently, even disposable LMAs are available.

Intubating Laryngeal Mask Airway The Intubating Laryngeal Mask Airway (ILMA) is an advanced version of the LMA allowing a special endotracheal tube to be passed through the ILMA into the trachea [15]. The device follows a two-stepconcept.First, it can be used as a rescue device in the unanticipated difficult airway to allow oxygenation and ventilation. Secondly, the ILMA serves as a conduit for endotracheal intubation without the need to visualize the vocal cords. A high cumulative success rate > 95% for endotracheal intubation with a maximum of three attempts is reported when conventional endotracheal intubation using a Mackintosh blade has failed. Disposable ILMAs in different sized have just become available.

Esophageal Tracheal Combitube The Esophageal Tracheal Combitube (ETC) is a double-lumen airway device designed for emergency ventilation when visualization of the vocal cords and thus endotracheal intubation is not possible [16]. With the ETC, the patient can be successfully ventilated regardless of whether the ETC is inserted into the trachea or into the esophagus. On blind insertion through the mouth the tube is more likely to pass into the esophagus (>95%) than into the trachea (<5%). If the ETC is placed in the esophagus, the distal balloon seals the esophagus and prevents regurgitation, while the proximal cuff seals the oropharyngeal space. Ventilation is achieved through a number of perforations situated between both cuffs. If placed in the trachea, the ETC functions as a standard endotracheal tube. The most common 380 C. Byhahn et al.

reason for ventilation failure in this setting is too deepplacement of the ETC, so that the perforated pharyngeal portion of the tube has entirely entered the esophagus. Pulling the ETC 3±4 cm back usually resolves this problem. If the tube passes into the trachea, the distal balloon is inflated, and ventilation is initiated via the distal lumen with no need to inflate the pharyngeal, proximal balloon. The ETC is only available in two sizes and cannot be used in patients <122 cm in height, is not reusable and is expensive. Beyond that, the device requires a certain amount of training that needs to be continuously refreshed. Despite its popu- larity amongst US health-care providers, it has not gained a similar level of popu- larity in Europe.

Laryngeal Tube The laryngeal tube is a single-lumen reusable or disposable tube inserted blindly into the esophagus. It has two cuffs sealing the pharyngeal airway and the esophageal inlet to an airway pressure of up to 40 mbar. Both cuffs are inflated through a single pilot tube and balloon. The ventilation outlet is situated between the cuffs [17]. There are three black lines on the tube near a standard 15 mm connector, which indicate adequate depth of insertion when aligned with the teeth. The device is available in all sizes from newborns to tall adults. A further development of the basic tube is the laryngeal tube with suction port, which is a second, small bore lumen not intended for ventilation, but for suctioning off gastric contents or insert- ing a gastric tube. The laryngeal tube is a technically simple, easy-to-use device with which ventilation can be initiated as fast as with BVM ventilation [18]. Im- proved efficacy of ventilation and fewer requirements for manual skills as compared to BVM ventilation may contribute to the replacement of BVM ventilation by the laryngeal tube in situations when basic ventilatory life support is provided by heath-care professionals untrained in more sophisticated emergency airway management.

Evaluation of Supraglottic Airway Devices According to the 2000 International Liaison Committee on Resuscitation (ILCOR) guidelines, endotracheal intubation is recommended as the gold standard for emergency airway management [19], although its contribution to outcome after cardiac arrest still remains controversial [20]. Acceptable alternatives to tracheal intubation and BVM ventilation include supraglottic airway devices, especially for those prac- titioners with limited experience in endotracheal intubation [19]. According to evidence based criteria, the ETC and the LMA have been evaluated to be easier to place than an endotracheal tube with similar complication rates, ventilation with both devices is comparable to that obtained with endotracheal intubation and definitely superior to BVM ventilation, and these devices are effective in case of failed endotracheal intubation [19]. It is beyond doubt that emergency physicians must be trained in the use of at least one of the supraglottic devices described above, and an alternative supraglottic device must be readily available in an emergency when endotracheal intubation fails. Current Concepts of Airway Management in the ICU and the Emergency Department 381

Modified Laryngoscope Blades Various modified laryngoscope blades are available to improve visualization of the glottic aperture and have proved useful when the Macintosh technique fails. The McCoy laryngoscope has an adjustable blade tip controlled by a lever on the handle, designed to lift the epiglottis without excessive leverage. It is definitely valuable in Cormack and Lehane grade III situations, but there is some doubt regarding its efficacy in the most difficult grade IV patients. Straight blades are often valuable in infants and small children. Unlike curved blades, they can be used to directly lift the epiglottis, thus improving the view to the glottic aperture. However, the paraglossal straight blade technique requires increased neck mobility, which is undesirable in trauma patients with anticipated cervical spine injuries. The Dærges universal laryngoscope blade (Fig. 1) has a low blade profile of only 16 mm, which makes introduction easier in patients with restricted mouth opening. Beyond that, the design of the blade allows its use in all patients > 10 kg body weight, thus replacing the traditional Macintosh size 2±4 blades. The most obvious benefit of this blade is a significant reduction in the number of blades that need to be held available for emergency intubation, and thus significant reduction of costs [21]. The video laryngoscope is a laryngoscope blade with a camera lens on its tip. The blade is fixed to the handle that incorporates the camera unit. Two armed wires connect the laryngoscope handle to an electric light source and a video screen. This technique has been described to improve the visualization of the lar- ynx to Cormack and Lehane grade I in patients with Cormack and Lehane grades III and IV under conventional laryngoscopy during elective endotracheal intubations. In emergency situations, however, the lens may be in contact with blood, secretions, and gastric contents, thereby worsening the indirect visualization of the glottis on the video screen. Beyond that, no wireless video signal transmission is possible yet, a 110/220 V light source is needed, and the technique requires a heavy video monitor, which significantly limits its potential value in emergency situations.

Fig. 1. The Dærges Universal Laryngoscope Blade has a low profile (16 mm) and can be used from children >10 kg to adults. (Reproduced with permission from Karl Storz GmbH, Tuttlingen, Germany) 382 C. Byhahn et al.

z Fiberoptic Devices

Two fiberoptic devices have a place in current emergency airway management strategies: Flexible fiberoptic bronchoscopes, and the Bonfils intubation fiberscope. The Bullard laryngoscope, a curved, rigid, laryngoscope device with an eyepiece attached to its handle, requires a high level of training, and has been widely replaced by the former devices.

Flexible Fiberoptic Bronchoscopy Fiberoptic endotracheal intubation in the awake, spontaneously breathing patient represents the gold standard for establishing a secure airway in patients with anticipated difficulties to conventional endotracheal intubation. Despite its unequalled value in elective patients under controlled in-hospital conditions, flexible fiberoptic bronchoscopy has some important limitations in airway emergencies. First of all, flexible fiberoptic bronchoscopy is restricted by its availability. Flexible fiberoptic bronchoscopes are expensive and, therefore, often not available in emergency de- partments or in the out-of-hospital environment, regardless of the fact that some flexible fiberoptic bronchoscopes can be used with a small battery-powered light source and thus independent of a large 110/220 V cold light source. Apart from limited availability, the lens often gets fogged or soiled with secretions or blood, which makes visualization of anatomical landmarks difficult, if not impossible. An- other important limitation is the fact that most emergency patients in whom flexible fiberoptic bronchoscopy would be potentially indicated because of unanticipated airway difficulties are unconscious, thus have decreased or no muscle tone, which results in difficult anatomy for fiberoptic intubation (i.e., the tongue is adja- cent to the pharyngeal wall in patients who are in the supine position). Considering this, flexible fiberoptic bronchoscopy is of minor value to resolve intubation difficulties in emergency situations.

Bonfils Intubation Fiberscope The adult Bonfils intubation fiberscope is a reusable, rigid, straight fiberoptic device with a 408 curved tip; 40 cm long and 5 mm in diameter. A flexible eyepiece is mounted on the handle of the scope. The fiberscope has a connector that fits onto the 15 mm tracheal tube adapter and thereby allows oxygen insufflation (Fig. 2), which also prevents fogging of the distal lens during the intubation procedure. A 110/220 V cold light source or a small battery handle (powered by two 1.5-V alka- line batteries) can be attached to the stylet handle. The tipof the Bonfils intubation fiberscope is positioned just proximal to the tip of the attached endotracheal tube (Fig. 2, inset), thereby preventing the lens from being soiled with blood or secretions to a significantly larger extent than those of a flexible fiberoptic bronchoscope. In recent studies, the Bonfils intubation fiberscope has proved its superiority and efficacy in patients with both predicted and unanticipated difficult airways re- quiring endotracheal intubation [22, 23]. Apart from its use in the operating room, the battery handle allows the Bonfils intubation fiberscope to be used in almost any situation, anywhere, i.e., in the field or in the emergency room, especially when definitive endotracheal intubation is required (e.g., in patients prone to regurgitation and aspiration). Current Concepts of Airway Management in the ICU and the Emergency Department 383

Fig. 2. Battery-powered Bonfils Intubation Fiberscope armed with an 8.0 mm ID endotracheal tube. The tipof the lens must be inside the endotracheal tube (see inset)

Many trauma victims are susceptible to cervical spine injury until this diagnosis has been ruled out by radiological examination. The cervical spine is therefore, ini- tially, immobilized by a rigid collar according to the Advanced Trauma Life Support (ATLS) protocol. Limited mouth opening and absent neck extension contribute to poor views on direct laryngoscopy (Cormack and Lehane grades III and IV) in 64% of patients with a rigid cervical collar [24]. Using an ultrasound-based motion system of the cervical spine, the potential benefit of the Bonfils intubation fiberscope was demonstrated during elective endotracheal intubation under general anesthesia in the hospital: the range of cervical spine movement, especially neck extension, was much greater with a standard Mackintosh blade (238Ô108) than with the Bonfils intubation fiberscope (68Ô58) [25]. The potential benefit of the Bonfils intubation fiberscope in trauma patients with suspected cervical spine injury is currently being evaluated by in-hospital and in-the-field trials. z Airway Considerations in the Intensive Care Unit

The algorithm for managing both anticipated and unanticipated difficult airway in the ICU is not different to that recommended by the American Society of Anesthe- siologists. There are, however, particular situations in the ICU and specific considerations regarding the patient's airway that require particular attention and skills of the intensivist in charge.

Lung Separation The indications for single-lung ventilation are classified either as absolute or as relative. The absolute indications include life-threatening complications such as mas- sive bleeding and abscess formation, to prevent spread to the non-diseased lung. Broncho-pleural and giant unilateral bullae may rupture under positive pressure ventilation, and modest invasive ventilation is mandatory. Finally, during broncho- alveolar lavage (BAL) for alveolar proteinosis or cystic fibrosis, prevention of con- tralateral lung drowning is absolutely necessary. When lung separation becomes indicated in the ICU, most patients are already intubated with a standard endotracheal tube. 384 C. Byhahn et al.

Techniques for single-lung ventilation can be accomplished in two different ways. The first involves the use of a double-lumen endotracheal tube. The second method involves blockade of a mainstem bronchus to allow lung collapse distal to the occlusion (bronchial blockers). Although double-lumen tubes are still the most common device used during lung separation techniques, bronchial blockade technology is on the increase.

Double-lumen Endotracheal Tubes: A double-lumen endotracheal tube is still the most frequently used device for single-lung ventilation and is considered as the gold standard for lung separation. The cuffed tip of the tube with its distal lumen is advanced either into the left or the right main bronchus, while the cuffed proximal lumen is placed in the trachea. If both cuffs are inflated and the tracheal lumen is occluded, only the left (left endobronchial double-lumen endotracheal tube) or right lung (right endobronchial double-lumen endotracheal tube) is ventilated. If the bronchial lumen is occluded, it is vice versa. The main advantage of a double-lumen endotracheal tube over any other devices for lung separation is its large bore lumina that allow for adequate suctioning, fiberoptic bronchoscopy of both lungs, and application of independent ventilation strategies to each lung. However, placement is difficult, if not impossible, in pa-

Table 2. Characteristics of various techniques for endobronchial blockade

Device/Technique Advantages Disadvantages z Endobronchial ± Easy, fast, and cheaptechnique ± No suction of the isolated lung possible intubation ± No PEEP can be applied to the isolated lung z Fogarty Catheter ± Can be used through the endo- ± Difficult to position tracheal tube in situ, no risk of ± Tends to dislocate airway loss z Univent Tube ± Intubation with a single lumen ± Placement of the integrated blocker tube usually requires fiberoptic control ± Ventilation does not need to ± Small lumen does not allow for ade- be discontinued during blocker quate suctioning of viscous secretions placement or blood z Arndt Endobronchial ± Can be used through the endo- ± Flexible fiberoptic bronchoscopy Blocker tracheal tube in situ, no risk of mandatory airway loss ± Small lumen does not allow for ade- ± Continuous ventilation possible quate suctioning of viscous secretions during blocker placement or blood ± Can be placed in almost any ± Re-positioning difficult in case of dislo- part of bronchial tree cation z Cohen Endobronchial ± Can be used through the endo- ± Placement usually requires fiberoptic Blocker tracheal tube in situ, no risk of control airway loss ± Small lumen does not allow for ade- ± Continuous ventilation possible quate suctioning of viscous secretions during blocker placement or blood ± Can be placed blindly in an ± Expensive emergency (e.g., pulmonary hemorrhage)

PEEP: positive end-expiratory pressure Current Concepts of Airway Management in the ICU and the Emergency Department 385 tients with a difficult airway (i.e., Cormack and Lehane grades III and IV). In patients with a standard endotracheal tube already in place, the tube needs to be removed before re-intubation with a double-lumen endotracheal tube can be attempted. Particularly in ICU patients, there is a certain risk of airway loss during tube exchange due to airway edema, hemorrhage, etc. Therefore, a variety of techniques and devices for endobronchial blockade have become available. Table 2 gives a comprehensive overview of currently available techniques and devices for blocker-facilitated lung separation.

Endobronchial Blockade: Endobronchial advancement of the single-lumen endotracheal tube in place is restricted to life-threatening emergencies to buy time until more appropriate lung separation techniques become available. The Fogarty occlusion embolectomy catheter is a device designed specifically to be used as a vascular tool; however, there are well documented reports of its use for lung isolation [26]. The occlusion balloon of the catheter is considered a high- pressure, low-volume cuff that requires 0.5±10 ml of air to achieve occlusion of a bronchus. The Fogarty catheter has an incorporated stylet that can be preshaped at the distal end to facilitate its guidance into the left mainstem bronchus. Advantages of the Fogarty catheter over a double-lumen endotracheal tube are as follows: it can be advanced through the lumen of an existing standard endotracheal or tracheostomy tube; and it can be used as a rescue device when lung separation is insufficient in patients who are already intubated with a double-lumen endotracheal tube. Disadvantages of the Fogarty technique are that the catheter is a vascular device, and neither designed nor certified as a bronchial blocker. Further it is made of nat- ural rubber latex, which is contraindicated in patients with latex allergy. The lack of a communicating channel in the center makes suction or oxygen insufflation impossible. Although the incorporated stylet facilitates insertion into a bronchus, it cannot be coupled to and navigated with a fiberoptic device. Keeping the catheter in a stable position once its balloon has been successfully advanced into a mainstem bronchus is also difficult, with a high risk of dislocation. Both endobronchial intubation and the use of a Fogarty catheter are, therefore, not reliable techniques for lung separation. The Univent tube is a single-lumen endotracheal tube with a channel enclosing a moveable bronchial blocker that can be used to block the left, right, or any specific secondary bronchus [27]. The channel that encloses the bronchial blocker has a diameter of only 2 mm which increases the anterior-posterior external diameter of the Univent tube, making the device larger than a single-lumen endotracheal tube of corresponding internal diameter. Because of its relative ease of placement, the Univent tube has been used in patients with hemoptysis or bleeding diathesis, and can be used during rapid sequence induction. By deflating and withdrawing the bronchial blocker the Univent tube can be converted to a conventional single- lumen endotracheal tube. Bronchoscopic guidance is usually required to successfully place the bronchial blocker. A definitive advantage of the Univent tube over a double-lumen endotracheal tube is that its placement is easier in patients with a difficult airway; however, sufficient suctioning of the isolated lung is impossible, and the blocker also tends to dislocate.

Wire-guided endobronchial blocker (Arndt-blocker): Another technique to achieve lung separation is the wire-guided endobronchial blocker, which is considered an independent bronchial blocker. Invented by the US anesthesiologist George A. 386 C. Byhahn et al.

Fig. 3. Wire-guided endobronchial blocker with Arndt Multiport Airway Adapter¾. a Blocker port with Touhy-Borst type valve; b bronchoscopy port; c ventilation port; d blocker with monofilament guide loop at its tip inserted into the airway adapter (Reproduced with permission from Cook Inc., Bloomington, IN, USA)

Arndt in 1999 [28], the wire-guided endobronchial blocker is a cuffed catheter available in different sizes (5, 7, and 9F outer diameter) and lengths (50, 65, and 78 cm). Its inner lumen contains a flexible nylon wire passing through the proximal end of the catheter, extending to the distal end, and then exiting as a small flexible wire loop. The wire loop of the Arndt blocker is coupled with a pediatric bronchoscope and serves as a guidewire to introduce the blocker into a bronchus under direct visualization. A special adapter with separate ports for the ventilator tube and the pediatric bronchoscope is attached to the endotracheal tube. Ventilation can therefore be maintained during bronchoscopy and placement of the blocker. The blocker itself is introduced through a third port with a Touhy-Borst type valve, locking the blocker in its final position and maintaining an air tight seal (Fig. 3). There are advantages to using the wire-guided endobronchial blocker over the double-lumen endotracheal tube or Univent tube in patients who are already tra- cheally intubated, who present with a difficult airway, or who require single-lung ventilation during acute trauma to the chest. In addition, it can be used as selective lobar blocker, e.g., in patients with previous pneumonectomy who require a selective one lobe ventilation. Because the wire-guided endobronchial blocker only requires a single-lumen tube, its use eliminates the need for tube exchange if me- chanical ventilation is contemplated in the postoperative period. One limitation of the wire-guided endobronchial blocker is that with the removal of the wire-guided loop it cannot be reinserted and thus intraoperative repositioning of the blocker can be difficult, especially during left mainstem bronchus intubation. Also the small diameter of the suction channel, which allows oxygenation and positive end-expiratory pressure (PEEP) application to the isolated lung, increases the time required for the lung to collapse and makes suctioning difficult. Figure 4 shows the thoracic computed tomography (CT) scan of a patient with bronchopleural fistula secondary to a tear in the distal portion of the right lower lobe bronchus. The wire-guided endobronchial blocker was used to selectively iso- late the right lower lobe, and the fistula closed within 24 hrs without further inter- vention [29]. Current Concepts of Airway Management in the ICU and the Emergency Department 387

Fig. 4. Thoracic CT scan of a patient with bronchopleural fistuala in whom the wire-guided endobronchial blocker was advanced from the trachea (a) into the right lower lobe bronchus (e)

Because fiberoptic control and guidance is mandatory for optimal placement of the wire-guided endobronchial blocker, the device is of little value in situations with difficult bronchoscopy conditions, such as in severe pulmonary hemorrhage.

Tip-deflecting endobronchial blocker (Cohen blocker): The 9F tip-deflecting endobronchial blocker, invented by thoracic anesthesiologist Edmund Cohen from New York in 2004, is closely related to the wire-guided endobronchial blocker, but does not have a guide wire loop coupled to a bronchoscope, rather an adjustable tip that can be deflected by 60 degrees with a small wheel, the rotation of which is trans- mitted to the blocker's tipby wires located inside the catheter. The tip-deflecting endobronchial blocker is intended to be placed under fiberoptic visualization; however, blind placement into the left or right main bronchus seems also possible in emergencies. Compared to the wire-guided endobronchial blocker, the tip-deflecting endobronchial blocker can only be placed into a main bronchus and thus is restricted to isolating an entire lung, and not a specific portion thereof. z Recent Developments in Percutaneous Tracheostomy

Tracheostomy Timing Percutaneous dilational tracheostomy has become an established treatment modali- ty for long-term airway access in the ICU during the past two decades. However, the optimal time to perform a percutaneous dilational tracheostomy has been based largely on personal experience and judgment rather than on medical evidence. In 388 C. Byhahn et al.

2004, Rumbak and colleagues published a milestone study evaluating the benefits of early (<48 hrs of intubation) versus delayed (>14 days of intubation) percutaneous dilational tracheostomy in medical ICU patients [30]. They found significant advantages of early percutaneous dilational tracheostomy in terms of facilitated weaning, shorter ICU length of stay, and incidence of nosocomial pneumonia. A recent meta-analysis of five prospective-randomized trials comparing early versus late tracheostomy in the ICU confirmed these results [5]. Based on the results of this meta-analysis that included Rumbak's data, intensivists should no longer delay tracheostomy in critically ill patients with an anticipated duration of intubation of more than 10±14 days.

Balloon Facilitated Percutaneous Tracheostomy Five different percutaneous dilational tracheostomy techniques are currently available: the classic Ciaglia technique using multiple dilators, the forceps dilational technique, the retrograde, translaryngeal technique, the single-dilator dilational Blue Rhino technique, and the PercuTwist technique using rotating dilation with a self-cutting screw. A potential disadvantage of all of these techniques is the require- ment of two independent steps: stoma creation by dilation, and subsequent cannula placement. Balloon facilitated percutaneous tracheostomy is an innovative technique basically invented by the pioneer in percutaneous dilational tracheostomy, Pasquale Ciaglia, shortly before his death in 2000, and refined by the pulmonologist Michael Zgoda from Kentucky, USA [31]. The novel approach to percutaneous dilational tracheostomy combines both steps ± dilation and cannula placement ± into a single

Fig. 5. Balloon facilitated percutaneous tracheostomy. An angioplasty balloon is inflated to 5 atm to dilate the stoma. After balloon deflation, the tracheostomy device is passed further into the trachea to advance the tracheostomy cannula Current Concepts of Airway Management in the ICU and the Emergency Department 389 step. The initial steps of the procedure are identical to any other technique: bronchoscopically guided tracheal puncture and subsequent guide wire placement. There- after, a special device is passed over the guide wire. The distal portion of the device is an angioplasty balloon filled with saline solution to create sufficient pressure to dilate the stoma. The proximal portion of the device is basically a loading dilator armed with a tracheostomy cannula. Once the distal portion of the balloon is seen inside the trachea, the balloon is inflated for 60 seconds (Fig. 5). Thereafter, the balloon is deflated, and the tracheostomy device is introduced further into the trachea, thus advancing the proximal portion of the device, which carries the cannula, into the trachea. Finally, the guide wire and tracheostomy device are removed, leaving only the cannula in situ. Once its correct intratracheal position has been bronchoscopically confirmed, the ventilator circuit can be connected to the cannula. Experience with balloon facilitated percutaneous tracheostomy is currently limited to animal [31] and cadaver studies [32, 33] and a few documented clinical cases [34]. There are potential benefits of this first real one-step percutaneous dilational tracheostomy technique, which will have to be confirmed in larger clinical trials before a definitive recommendation regarding the clinical impact of balloon facilitated percutaneous tracheostomy can be made. z Conclusion

Concurrent failure of tracheal intubation and mask ventilation may ultimately result in death or brain damage. Therefore, these two basic techniques are the most important that any emergency physician has to learn. An increasing number of airway devices and techniques has been developed to manage the unanticipated airway in the field or in the emergency department. Successful use of any alternative technique to endotracheal intubation requires a high level of continuous training especially when endotracheal intubation has failed. The skills and experience of a res- cuer performing basic or advanced airway management determine whether these maneuvers result in effective oxygenation or serious complications, such as severe neurological impairment or even death [35]. Recently published data and a meta-analysis clearly advocate abandoning the prevailing practice of performing tracheostomy in critically ill patients around day 10 of endotracheal intubation, and supports performing early tracheostomy instead. Balloon facilitated percutaneous tracheostomy is a recently introduced, one-step tracheostomy technique that needs further clinical evaluation.

References

1. Walls RM (1996) Rapid-sequence intubation comes of age. Ann Emerg Med 28:79±81 2. Gerich TG, Schmidt U, Hubrich V, Lobenhoffer HP, Tscherne H (1998) Prehospital airway management in the acutely injured patient: the role of surgical cricothyrotomy revisited. J Trauma 45:312±314 3. Adnet F, Jouriles NJ, Le Toumelin P, et al (1998) Survey of out-of-hospital emergency intubations in the French prehospital medical system: a multicenter study. Ann Emerg Med 32:454±460 4. Wang HF, Sweeney TA, O'Connor RE, Rubinstein H (2001) Failed prehospital intubation: an analysis of emergency department courses and outcomes. Prehosp Emerg Care 5:132±141 390 C. Byhahn et al.

5. Griffiths J, Barber VS, Morgan L, Young JD (2005) Systematic review and meta-analysis of studies of the timing of tracheostomy in adult patients undergoing artificial ventilation. BMJ 330:1243±1246 6. Karch SB, Lewis T, Young S, Hales D, Ho CH (1996) Field intubation of trauma patients: complications, indications, and outcomes. Am J Emerg Med 14:617±619 7. Langeron O, Masso E, Huraux C, et al (2000) Prediction of difficult mask ventilation. An- esthesiology 92:1229±1236 8. Stone BJ, Chantler PJ, Baskett PJ (1998) The incidence of regurgitation during cardiopulmonary resuscitation: a comparison between bag valve mask and laryngeal mask airway. Resuscitation 38:3±6 9. Lawes EG, Baskett PJ (1987) Pulmonary aspiration during unsuccessful cardiopulmonary aspiration. Intensive Care Med 13:379±382 10. Bowman FP, Menegazzi JJ, Check BD, Duckett TM (1995) Lower esophageal sphincter pressure during prolonged cardiac arrest and resuscitation. Ann Emerg Med 26:216±219 11. Brain AI, McGhee TD, McAteer EJ, Thomas A, Abu-Saad MA, Bushman JA (1985) The laryngeal mask airway. Development and preliminary trials of a new type of airway. Anaesthe- sia 40:356±361 12. Dærges V, Ocker H, Wenzel V, Sauer C, Schmucker P (2001) Emergency airway management by non-anaesthesia house officers. A comparison of three strategies. Emerg Med J 18:90±94 13. Dunford JV, Davis DP, Ochs M, et al (2003) Incidence of transient hypoxia and pulse rate reactivity during paramedic rapid sequence intubation. Ann Emerg Med 42:721±728 14. Nolan JD (2001) Prehospital and resuscitative airway care: Should the gold standard be re- assessed? Curr Opin Crit Care 7:413±421 15. Brain AI, Verghese C, Addy EV, Kapila A, Brimacombe J (1997) The intubating laryngeal mask. II: A preliminary clinical report of a new means of intubating the trachea. Br J Anaesth 79:704±709 16. Frass M, Frenzer R, Zdrahal F, Hoflehner G, Porges P, Lackner F (1987) The esophageal tracheal combitube: Preliminary results with a new airway for CPR. Ann Emerg Med 16:768± 772 17. Dærges V, Ocker H, Wenzel V, Schmucker P (2000) The laryngeal tube: A new simple airway device. Anesth Analg 90:1220±1222 18. Kurola J, Harve H, Kettunen T, et al (2004) Airway management in cardiac arrest. Compari- son of the laryngeal tube, tracheal intubation, and bag-valve mask ventilation in emergency medical training. Resuscitation 61:149±153 19. Guidelines 2000 for cardiopulmonary resuscitation and emergency cardiovascular care. Part 6: advanced cardiovascular life support: section 3: adjuncts for oxygenation, ventilation and airway control. The American Heart Association in collaboration with the International Liaison Committee on Resuscitation (2000). Circulation 102 (suppl 8):I95±104 20. Barnes TA, MacDonald D, Nolan J, et al (2001) Cardiopulmonary resuscitation and emergency cardiovascular care. Airway devices. Ann Emerg Med 37 (suppl 4):S145±151 21. Gerlach K, Wenzel V, von Knobelsdorff G, Steinfath M, Dærges V (2003) A new universal laryngoscope blade. A preliminary comparison with Macintosh laryngoscope blades. Resus- citation 57:63±67 22. Bein B, Worthmann F, Scholz J, et al (2004) A comparison of the intubating laryngeal mask airway and the Bonfils intubation fibrescope in patients with predicted difficult airways. Anaesthesia 59:668±674 23. Bein B, Yan M, Tonner PH, Scholz J, Steinfath M, Dærges V (2004) Tracheal intubation using the Bonfils intubation fibrescope after failed direct laryngoscopy. Anaesthesia 59:1207±1209 24. Heath KJ (1994) The effect on laryngoscopy of different cervical spine immobilization techniques. Anaesthesia 49:843±845 25. Wahlen BM, Gercek E (2004) Three-dimensional cervical spine movement during intubation using the Mackintosh and Bullard laryngoscopes, the Bonfils fiberscope and the intubating laryngeal mask airway. Eur J Anaesthesiol 21:907±913 26. Ginsberg RJ (1981) New technique for one-lung anesthesia using an endobronchial blocker. J Thorac Cardiovasc Surg 82:542±546 27. Inoue H, Shohtsu A, Ogawa J, Kawada S, Koide S (1982) New device for one-lung anesthesia: Endotracheal tube with movable blocker. J Thorac Cardiovasc Surg 83:940±941 Current Concepts of Airway Management in the ICU and the Emergency Department 391

28. Arndt GA, DeLessio ST, Kranner PW, Orzepowski W, Ceranski B, Valtysson B (1999) One- lung ventilation when intubation is difficult ± Presentation of a new endobronchial blocker. Acta Anaesthesiol Scand 43:356±358 29. Byhahn C, Meininger D, Thærner M, Zwissler B (2004) Selective lobe isolation in thoracic trauma using a fiberoptically directed wire-guided endobronchial blocker. Anesthesiology 101:B11 30. Rumbak MJ, Newton M, Truncale T, Schwartz SW, Adams JW, Hazard PB (2004) A prospective, randomized study comparing early percutaneous dilational tracheotomy to prolonged translaryngeal intubation (delayed tracheotomy) in critically ill medical patients. Crit Care Med 32:1689±1694 31. Zgoda M, Berger R (2003) Balloon facilitated percutaneous tracheostomy tube placement: A novel technique. Chest 124:130S±131S 32. Zgoda M, deBoisblanc B, Berger R (2004) Balloon facilitated percutaneous dilational tracheostomy: a human cadaver feasibility study. Chest 126:735S 33. Zgoda M, deBoisblanc B, Byhahn C (2005) Balloon facilitated percutaneous dilational tracheostomy: entire experience of this novel technique. Proc Am Thorac Soc 2:A439 34. Zgoda M, Byhahn C (2005) Balloon facilitated percutaneous tracheostomy: Does it really work? Intensive Care Med 31:A146 35. Pepe PE, Zachariah BS, Chandra NC (1993) Invasive airway techniques in resuscitation. Ann Emerg Med 22:393±403